Electronic cameras are commonly used to capture both still and moving images. The images can be viewed immediately or stored for later viewing and printing. Systems using real-time display of moving images are useful for applications in surveillance and when the viewer is remote from the scene to be imaged, for example surveying drains or in endoscopic medical investigations. All these cases involve the display of the image information in a visible form.
Commercially available electronically addressed tactile panels such as the Papenmeier Braillex, manufactured by F.H. Papenmeier GmbH & Co. KG of Germany, exist to allow visually impaired people to read Braille-encoded text. They usually provide just 40 (or sometimes 80) 6- or 8-dot cells, each cell depicting a text character. See http://snow.utoronto.ca/technology/products/refreshable-braille.html
The need for a tactile computer screen has been recognized. For example, the concept of a system capable of a full screen of text is described in U.S. Pat. No. 4,871,992.
U.S. Pat. No. 5,842,867 describes a graphic tactile cell for indicating a graphic pattern, in which the arrangement of the tactile surface can be enlarged easily. This graphic tactile cell includes tactile pins for indicating a graphic pattern by vertical movement, piezoelectric element segments which are bent upon application of a voltage to vertically drive the tactile pins, and a unit base for holding the tactile pins and the piezoelectric element segments. A plurality of cell units each including a unit number of tactile pins, corresponding piezoelectric element segments, and a unit base for holding the tactile pins and the piezoelectric element segments are coupled vertically and horizontally such that the tactile pins are arranged at an equal interval in vertical and horizontal directions. Proximal ends of the piezoelectric element segments are held by the unit base through plastically deformable adjusting members.
U.S. Pat. No. 6,109,922 describes a perforated plate with axial pins positioned in at least two stable positions with electromechanical actuators for this purpose.
Such devices have been demonstrated for use with line images derived from two dimensional digital images by the National Institute for Standards and Technology, Gaithersburg. In this device lines are produced by using pins raised to a single position above the plane of the display tablet.
U.S. Pat. No. 6,298,010 discloses an “orientation aid for the blind and visually disabled”. This consists of a distance measuring system consisting of a projected single beam and reflected beam detector whose signal can be interpreted as the distance of the device from the reflecting object. This distance is indicated by a tactile indicator.
Another device to aid the blind appreciate the surrounding area is one which emulates the process of the blind person who uses reflected sound from the tapping of a stick to provide some awareness of obstacles such as walls. U.S. application No. 2001/0016818 A1 describes a device for analyzing sound in terms of an amplitude versus frequency relationship and converting amplitude signals in several discrete frequency regions into control signals. The control signals are used to control a linear array of tactile transducers which are sensed by the user.
Systems for producing three dimensional objects from three dimensional image information exist. For example, 3-D Systems Inc. produce a number of products enabling the production of three dimensional objects from Computer-Aided Design systems. One such “Solid Object Printer” is the “ThermoJet” printer. This is a type of inkjet printer using a melted wax ink which, after deposition, dries to form a layer of wax. The object is built up from several layers of wax.
Three dimensional relief objects can be produced by vacuum forming techniques. In such techniques, a first surface is produced for the purpose of forming a further surface conforming to the shape of the first surface, the further surface being formed by a material which can be deformed to the required shape and then becomes rigid to hold the deformed shape. The lack of re-entrant angles allows the easy removal of the rigid further surface. Typically, a sheet of thermoplastics material is heated so that it softens and is then laid over the first forming surface. Using suitable techniques, air can be extracted from between the forming surface and the thermoplastics sheet. Atmospheric pressure then forces the sheet to conform with the forming surface. The sheet becomes rigid on cooling.
Problem to be solved by the Invention
The information in a visible image, i.e., the spatial distribution of light intensity or brightness, which could be displayed to a blind person using a tactile panel is not particularly useful. The shape of an object is much more useful information in this case. The blind person also needs an appreciation of the nearness of objects, particularly dangerous objects such as moving vehicles. It is far more useful to have a two-dimensional array of distance indicators which can be scanned by touch than a device for sampling only one element of such an array at any one time.
A problem to be solved is that of providing an aid to the orientation of a blind person who has little or no ability to detect features of the surroundings which may put him or her at risk. The problem is, therefore, to provide images of the scene in a way which conveys three-dimensional information in real time. This would allow the person to be aware of features of the floor or ground such as steps or curbs, obstructions such as furniture or lamp-posts, nearby people or animals or potentially dangerous traffic. Preferably, the form of the image produced is a dynamic three dimensional form.
Another problem to be solved is the provision of permanent or quasi permanent three dimensional relief images in a convenient and inexpensive way. Such relief images would be useful as records of original objects or scenes, such as faces or buildings, which can then be appreciated by blind people by touch. It would be useful for blind and visually impaired people to have access to such relief images or alternatively to have access to the information in digital form and use a suitable device to produce the relief image. This relief image may be a permanent image or a temporary image in a device capable of generating three dimensional surfaces. This device could be the same as the device suitable for providing real time dynamic three dimensional surfaces.
It will be appreciated that any apparatus capable of providing such three dimensional surfaces can also be used by sighted people who can appreciate the three dimensional surface by sight as well as by touch.